Update closeKeyboardWhenScrolling documentation

[julien-levarlet]

Hi,
I was working with the closeKeyboardWhenScrolling attribute and I noticed that the documentation doesn't mention that the focusNode has to be set to make it work. It updated the doc string to make it clearer.

In the code below, if no focusNode is set, the condition will always be false

if (widget.closeKeyboardWhenScrolling &&
          widget.focusNode?.hasFocus == true) {
    FocusScope.of(context).requestFocus(FocusNode());
}

[koukibadr]

@julien-levarlet good catch thank you, but looking back at this maybe it's better if the check on the focus node is removed to ease the usage of the flag closeKeyboardWhenScrolling because it may cause conflict with the app code

[julien-levarlet]

Yes, simplifying its use can be great.
But removing the check will probably remove focus on other widget if the search bar was not on focus. Will it be ok ?

[koukibadr]

Yes that make sense since the flag is called closeKeyboardWhenScrolling so it's intended that the focus will reset in the screen